 The proposed practical approach involves using hollow porous and doped carbon capsules loaded with ruthenium clusters modified with a cationic polymeric network to selectively remove 99 TCO4 minus or its surrogate Rio4 minus under extreme conditions. An electrochemical redox process is used to transform adsorbed Rio4 minus to bulk Rio3, delivering record high removal capacities and excellent long-term durability for removing Rio4 minus in simulated nuclear waste streams and alkaline high-level waste streams. In Cituraman and X-ray absorption spectroscopy analyses show that adsorbed Rio7 is electrocatalytically reduced on roof sites to a Rio4-O2 intermediate, which can then be re-oxidized to insoluble Rio6-O3 for facile collection.